cola/compat.py

   1 # pylint: disable=unused-import,redefined-builtin,undefined-variable
   2 from __future__ import absolute_import, division, unicode_literals
   3 import os
   4 import sys
   5
   6 try:
   7     import urllib2 as parse  # noqa
   8 except ImportError:
   9     # Python 3
  10     from urllib import parse  # noqa
  11
  12
  13 PY2 = sys.version_info[0] == 2
  14 PY3 = sys.version_info[0] >= 3
  15 PY26_PLUS = PY2 and sys.version_info[1] >= 6
  16 WIN32 = sys.platform == 'win32' or sys.platform == 'cygwin'
  17 ENCODING = 'utf-8'
  18
  19
  20 if PY3:
  21
  22     def bstr(x, encoding=ENCODING):
  23         return bytes(x, encoding=encoding)
  24
  25
  26 elif PY26_PLUS:
  27     bstr = bytes
  28 else:
  29     # Python <= 2.5
  30     bstr = str
  31
  32 if PY3:
  33
  34     def bchr(i):
  35         return bytes([i])
  36
  37     int_types = (int,)
  38     maxsize = sys.maxsize
  39     ustr = str
  40     uchr = chr
  41 else:
  42     bchr = chr
  43     maxsize = 2 ** 31
  44     # pylint: disable=unicode-builtin
  45     ustr = unicode  # noqa
  46     # pylint: disable=unichr-builtin
  47     uchr = unichr  # noqa
  48     # pylint: disable=long-builtin
  49     int_types = (int, long)  # noqa
  50
  51 # Qt's max 32-bit signed integer range (-2147483648 to 2147483647)
  52 maxint = (2 ** 31) - 1
  53
  54
  55 def setenv(key, value):
  56     """Compatibility wrapper for setting environment variables
  57
  58     Why?  win32 requires putenv().  UNIX only requires os.environ.
  59
  60     """
  61     if not PY3 and isinstance(value, ustr):
  62         value = value.encode(ENCODING, 'replace')
  63     os.environ[key] = value
  64     os.putenv(key, value)
  65
  66
  67 def unsetenv(key):
  68     """Compatibility wrapper for unsetting environment variables"""
  69     os.environ.pop(key, None)
  70     if hasattr(os, 'unsetenv'):
  71         os.unsetenv(key)
  72
  73
  74 def no_op(value):
  75     """Return the value as-is"""
  76     return value
  77
  78
  79 def byte_offset_to_int_converter():
  80     """Return a function to convert byte string offsets into ints
  81
  82     Indexing into python3 bytes returns ints, Python2 returns str.
  83     Thus, on Python2 we need to use `ord()` to convert the byte into
  84     an integration.  It's already an int on Python3, so we use no_op there.
  85
  86     """
  87     if PY2:
  88         result = ord
  89     else:
  90         result = no_op
  91     return result